<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2016, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package    CodeIgniter
 * @author    EllisLab Dev Team
 * @copyright    Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright    Copyright (c) 2014 - 2016, British Columbia Institute of Technology (http://bcit.ca/)
 * @license    http://opensource.org/licenses/MIT	MIT License
 * @link    https://codeigniter.com
 * @since    Version 1.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * Benchmark Class
 *
 * This class enables you to mark points and calculate the time difference
 * between them. Memory consumption can also be displayed.
 *
 * @package        CodeIgniter
 * @subpackage    Libraries
 * @category    Libraries
 * @author        EllisLab Dev Team
 * @link        https://codeigniter.com/user_guide/libraries/benchmark.html
 */
class CI_Benchmark
{

    /**
     * List of all benchmark markers
     *
     * @var    array
     */
    public $marker = array();

    /**
     * Set a benchmark marker
     *
     * Multiple calls to this function can be made so that several
     * execution points can be timed.
     *
     * @param    string $name Marker name
     * @return    void
     */
    public function mark($name)
    {
        $this->marker[$name] = microtime(TRUE);
    }

    // --------------------------------------------------------------------

    /**
     * Elapsed time
     *
     * Calculates the time difference between two marked points.
     *
     * If the first parameter is empty this function instead returns the
     * {elapsed_time} pseudo-variable. This permits the full system
     * execution time to be shown in a template. The output class will
     * swap the real value for this variable.
     *
     * @param    string $point1 A particular marked point
     * @param    string $point2 A particular marked point
     * @param    int $decimals Number of decimal places
     *
     * @return    string    Calculated elapsed time on success,
     *            an '{elapsed_string}' if $point1 is empty
     *            or an empty string if $point1 is not found.
     */
    public function elapsed_time($point1 = '', $point2 = '', $decimals = 4)
    {
        if ($point1 === '') {
            return '{elapsed_time}';
        }

        if (!isset($this->marker[$point1])) {
            return '';
        }

        if (!isset($this->marker[$point2])) {
            $this->marker[$point2] = microtime(TRUE);
        }

        return number_format($this->marker[$point2] - $this->marker[$point1], $decimals);
    }

    // --------------------------------------------------------------------

    /**
     * Memory Usage
     *
     * Simply returns the {memory_usage} marker.
     *
     * This permits it to be put it anywhere in a template
     * without the memory being calculated until the end.
     * The output class will swap the real value for this variable.
     *
     * @return    string    '{memory_usage}'
     */
    public function memory_usage()
    {
        return '{memory_usage}';
    }

}
